window.onload=function(){
   var popwindow=document.getElementsByClassName('popwindow')[0];
   var hidden=document.getElementsByClassName('hidden')[0];
   var close=document.getElementsByClassName('close')[0];
   var login=document.getElementById('login');
   var register=document.getElementById('register');
   var btn01=document.getElementById('btn01');
   var btn02=document.getElementById('btn02');

   login.onclick=function(){
      popwindow.style.display='block';
      hidden.style.display='block';
      console.log(123);
   }
   register.onclick=function(){
      popwindow.style.display='block';
      hidden.style.display='block';
   }
   close.onclick=function(){
      popwindow.style.display='none';
      hidden.style.display='none';
   }
   hidden.onclick=function(){
      popwindow.style.display='none';
      hidden.style.display='none';
   }
   btn01.onclick=function(){
      window.location.href="./login.html"
   }
   btn02.onclick=function(){
      window.location.href="./register.html"
   }
}